KR980009986A - Fluid Bearings With Spacers - Google Patents

Abstract

Disclosed is a fluid bearing having a spacer. The fluid bearing has a pair of inner races fixed to face each other on a rotating shaft, a lubrication surface corresponding to the lubrication surface of the inner race, and an outer race that moves relative to the inner race, and is installed between the inner race and between the inner race and the outer race. In a fluid bearing having a spacer having a spacer for maintaining clearance, the gap between the outer ring and the spacer is characterized in that the spacer can serve as a journal bearing. The present invention having such a feature can provide a fluid bearing having a spacer excellent in radial load characteristics without changing the size of the appearance.

Description

Fluid Bearings With Spacers

1 is a cross-sectional view of a fluid bearing with a conventional spacer.

2 is a cross-sectional view of a fluid bearing with a spacer according to the present invention.

3 is a partially cutaway perspective view of the spacer of FIG.

* Explanation of symbols for main parts of the drawings

10: Shaft 20: Upper inner ring

30: lower inner ring 50: outer ring

60: Ring 70: Spacer

71 ： Groove 72 ： Titanium coating film

73 ： DLC coating film

[Purpose]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluid bearing having a spacer having excellent radial load characteristics without a change in outer size.

[Technical field to which the person belongs and the prior art in that field]

The present invention relates to a fluid bearing, and more particularly to a fluid bearing having a spacer.

Fluid bearings with spacers include hemispherical fluid bearings, conical fluid bearings, and the like. Such fluid bearings are used where high speed rotation is required. For example, hemispherical fluid bearings are used in spindle motors such as hard disk drives, motors for rotating rotary mirrors used in laser printers or laser scanners. In general, a fluid bearing having a spacer is small in size, and can be called a fluid bearing as long as it can support a large force acting in the axial direction and the radial direction. That is, the fluid bearing may have large axial and radial load characteristics.

1 is a cross-sectional view showing a conventional hemispherical fluid bearing. As shown, the conventional hemispherical fluid bearing is fixed to the shaft (1) to face each other, the upper inner ring (2) and lower inner ring (3) having a spherical outer peripheral surface, and the upper inner ring (2) and lower inner ring (3) an outer ring (5) surrounding the ring, a ring (6) for compressing the upper inner ring (2) and the lower inner ring (3) from being separated from the shaft (1), the upper inner ring (2) and the lower inner ring (3) And a spacer 7 positioned between the upper and lower inner races 2 and 3 to maintain the clearance between the outer race 5.

Since the clearance between the upper and lower inner rings 2 and 3 and the outer ring 5 is interposed with a liquid or gas that is lubricating oil, the upper and lower inner rings 2 and 3 and the outer ring 5 rotate without being contacted by relative movement. Can be.

On the other hand, the radial load characteristic applied to the hemispherical fluid bearing according to the prior art is determined by the size of the radius or the clearance of the upper inner ring 2 and the lower inner ring 3. In devices requiring large load characteristics in the radial direction, a large upper inner ring 2 and a large lower inner ring 3 have to be installed or the clearance is small, but due to the structural characteristics of the device, the upper inner ring 2 and the lower inner ring 2 In many cases, it is not possible to increase the size of, and in some cases, the clearance cannot be made small due to workability and assembly properties.

[Technical Challenges to be Done]

It is to realize a fluid bearing having a spacer having excellent radial load characteristics without any change in outer size.

[Configuration and Actions of Persons]

A fluid bearing having a spacer according to the present invention for achieving the above object includes: a pair of inner rings fixed to face each other on a rotating shaft, and a lubricating surface corresponding to the lubricating surface of the inner ring and having relative rotational movements. In the fluid bearing having a outer ring and a spacer provided between the inner ring and the spacer to maintain the clearance between the inner ring and the outer ring, the gap between the outer ring and the spacer can act as a journal bearing It is characterized in that the interval. Preferably, the gap between the outer ring and the spacer is equal to the clearance between the inner ring and the outer ring. And, preferably, a groove is formed on the main surface of the spacer.

The fluid bearing having a spacer according to the present invention having such a feature is excellent in radial load characteristics without a change in the size of the outer shape.

Hereinafter, a preferred embodiment of a fluid bearing having a spacer according to the present invention with reference to the accompanying drawings will be described in detail.

Referring to Figure 2, the technical concept of the present invention not only to maintain the clearance between the upper, lower inner ring (20, 30) and the outer ring 50, the role of the spacer 70 used in the fluid bearing having a spacer It is characterized by the fact that the radial load characteristics of the hemispherical fluid bearing are increased by acting as a journal bearing.

Referring to the fluid bearing having a spacer according to the present invention taking a hemispherical fluid bearing as an example.

The hemispherical fluid bearing has a spherical outer circumferential surface and an outer ring 50 that is relatively rotated with the upper inner ring 20 and the lower inner ring 30 fixed to face each other on the shaft 10, and the upper inner ring 20 and the lower inner ring 30. ), A ring 60 for pressing the upper inner ring 20 and the lower inner ring 30 so as not to be separated from the shaft 10, and an upper and lower inner ring 30 between the upper inner ring 20 and the lower inner ring 30. It is configured to include a spacer 70 to maintain the clearance between the (20, 30) and the outer ring 50 and serves as a journal bearing. Here, the ring 60 and the shaft 10 can be combined, for example in an interference fit or screw structure.

The spacer 70 is fixed to the shaft 10 or the inner ring 20 to move relative to the outer ring 50 together with the shaft 10. In addition, the clearance between the spacer 70 and the outer ring 50 may include a clearance between the hemispheres 20 and 30 and the outer ring 50 so that the spacer 70 may act as the outer ring 50 to serve as a journal bearing. It is the same interval.

The radial load characteristic applied to the hemispherical fluid bearing is increased by the bearing role of the spacer 70. That is, the radial load capacity of the conventional hemispherical fluid bearing was the sum of the load capacity of the upper inner ring and the load capacity of the lower inner ring, but the radial load capacity of the hemispherical fluid bearing according to the present invention is the load capacity of the upper inner ring 20. , The load capacity of the lower inner ring 30 and the load capacity of the spacer 70 are added.

Meanwhile, referring to FIGS. 2 and 3, a titanium (Ti) film having a thickness of 5 μm-20 μm may be coated on the upper, lower inner rings 20 and 30 and the spacer 70 mainly made of high carbon steel or WCo. have. Similarly, a titanium film having a thickness of 5 µm-20 µm may be coated on the lubricating surface of the outer ring 50 mainly composed of high carbon steel or WCo. The upper inner ring 20, the lower inner ring 30, the spacer 70 and the outer ring 50 may be formed of a coating film made of ceramic, for example Al2O3, instead of the titanium coating film 73, and the upper, lower inner ring 20, 30), the spacer 70 and the outer ring 50 may be made of a ceramic material.

Referring to Fig. 3, DLC (Diamond) having a thickness of 50-10 mu m on the titanium coating film 73 coated on the spacer 70 to reduce wear due to solid friction between the spacer 70 and the outer ring 50 at the start. Like Carbon) 72 may be coated.

A groove 71 is formed on the main surface of the spacer 70. This groove 71 is formed in the DLC coating film 72. The groove 71 may extend beyond the DLC coating layer 72 to the titanium coating layer 73 according to the thickness of the DLC coating layer 71 if necessary. The groove 71 generates oil or air pressure when the spacer 70 is rotated to increase the safety of the rotation system including the bearing at high speed.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will be able to practice various modifications and other equivalent embodiments therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the present invention.

[Effects of people]

The hemispherical fluid bearing according to the present invention has a large radial load characteristic without a change in the size of the contour.

Claims (9)

A pair of inner rings fixed to face each other on a rotating shaft, a lubricating surface corresponding to the lubricating surface of the inner ring, and an outer ring for relative rotational movement with the inner ring, and a clearance provided between the inner ring and the outer ring A fluid bearing having a spacer having a spacer for holding a fluid, wherein the gap between the outer ring and the spacer is an interval at which the spacer can serve as a journal bearing. 2. The fluid bearing of claim 1, wherein a distance between the outer ring and the spacer is equal to a clearance between the inner ring and the outer ring. The fluid bearing having a spacer according to claim 1 or 2, wherein a groove is formed on a main surface of the spacer. The fluid bearing having a spacer according to claim 1 or 2, wherein a first coating film made of titanium or ceramic is formed on a lubrication surface of at least one of the outer ring and the spacer. The fluid bearing having a spacer according to claim 4, wherein a second coating film made of DLC is further formed on the first coating film. 6. The fluid bearing of claim 5, wherein a predetermined groove is formed in the second coating layer. The fluid bearing of claim 6, wherein the groove extends to the first coating layer. The fluid bearing with a spacer according to any one of claims 4 to 7, wherein the first coating film has a thickness of 5 µm to 20 µm. The fluid bearing with a spacer according to any one of claims 4 to 7, wherein the thickness of the second coating film is 0.5 µm to 5 µm. ※ Note: The disclosure is based on the initial application.